1National Institute of Virology, Pune-411001, India.
2All India Institute of Medical Sciences, Delhi
3King Institute of Preventive Medicine, Chennai
4Virus Research Unit (VRU), National Institute of Cholera And Enteric Diseases, Kolkata
5Regional Medical Research Center, Dibrugarh, India.
Abstracts of the papers presented at the International Conference of Indian Virological Society on “Emerging and Re-emerging viral Diseases of the Tropics and Subtropics” at Indian Agricultural Research Institute, New Delhi, India, December 11–14, 2007.
Influenza type B makes up an important component of the overall disease burden of influenza in humans. Since 1987, the influenza B viruses have been categorized as belonging to two antigenically & genetically distinct lineages represented by B/Victoria/2/87 (as Victoria) and B/Yamagata/16/88 (as Yamagata). Phylogenetic analyses of HA gene of influenza B viruses circulating in India during 2005–2006. At the National Institute of Virology, Pune genetic characterization of 29 type B influenza strains [Pune (19), Delhi (4), Chennai(4), Dibrugarh(1) and Kolkata(1)] from different geographical areas of India, was carried out. RT-PCR was done. Further sequencing of HA1 domain of HA gene was done. Comparison between reference and circulating strains was analyzed by the construction of phylogenetic tree using MEGA 3.1 version. Fragments of 1044 bp of HA gene from type B isolates were amplified and sequenced. Phylogenetic analyses indicated that both the lineages of type B were circulating in India during 05–06. WHO recommended B/Shanghai/361/2002 (Yamagata lineage) as type B vaccine component for the period November 04 to April 06.As in India during January 2005 – March 2006 both type B lineages were co-circulating with predominance of viruses of Victoria lineage. WHO recommended vaccine (04–05 & 05–06) may not have been relevant against Indian strains circulating in 2005–2006.Our study suggests that continuous monitoring of the two type B lineages is important for better selection of appropriate vaccine component.
